Reference Energies in Semiempirical Parametrizations.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• The Modified Neglect of Diatomic Overlap (MNDO) is a semi-empirical quantum chemistry method.
• Accurate parametrization is crucial for the predictive power of computational methods.

Purpose of the Study:

• To reparametrize the MNDO scheme specifically for hydrocarbons.
• To validate the use of experimental data for parametrization.

Main Methods:

• Reparametrization of the MNDO scheme using molecular binding energies.
• Utilizing heats of formation at 0 K as experimental reference data.
• Comparison of results with the original MNDO parameters.

Main Results:

• Minor adjustments to optimized parameters were observed after reparametrization.
• The reparametrized scheme maintained essentially the same level of accuracy as the original MNDO.
• The study confirmed the validity of using heats of formation at 298 K.

Conclusions:

• The reparametrization of MNDO for hydrocarbons yields results comparable to the original method.
• The use of heats of formation at 298 K is justified for MNDO parametrization.
• The MNDO method remains a viable tool for hydrocarbon calculations.